Kadee #178 HO #158 “Scale” Whisker Metal Couplers & Scale Gearboxes Medium (9/32″) Centerset Shank – 11-0178 The #178 Kadee Magne-Matic Coupler features a “Scale” Metal Whisker Coupler (a smaller head coupler which is more to scale and is patterned after the type ‘E” couplers), insulated “Scale” Draft Gear Box and Lid with rear and center screw holes for mounting. 2-56 screws are the most commonly used for center hole. 0-48 or 0-80 screws are used for rear hole. Screw length will very depending on the mounting situation. It is not recommended to use a metal coupler directly on a metal surface or in a metal draft gearbox to avoid possible electrical crossover and shorting that may cause damage. Two pair per package. (2) Pair #178 Scale Whisker Metal Couplers – Medium Centerset Shank (2) Pair #178 Scale Snap-Together Gearboxes and lids (2) #625 Knuckle Springs This item is intended for modelling use and is not a toy. Actual product may vary slightly from the pictures shown.